1. Field of the Invention
The present invention relates to avionics systems, and more particularly, to systems and methods for monitoring and testing performance of transponders such as air traffic control-related transponders installed in aircraft.
2. Description of the Related Art
Travel by aircraft is generally a safe and efficient way for travelers to reach remote destinations. Over the years, as the popularity of air travel has dramatically increased, the need for techniques for safely managing the flow of aircraft has also risen. To address air traffic safety issues, aircraft have been equipped with avionics equipment such as transponders that assist air traffic controllers in identifying, tracking, and managing aircraft in flight. Transponders provide air traffic controllers with information such as aircraft identification, altitude and other aircraft-specific data, allowing controllers to more effectively manage air traffic.
To ensure that avionics continue to function as originally designed, the Federal Avionics Administration (FAA) has established tests that must be performed on aircraft equipment on a periodic basis. Aircraft equipped with ATC transponders (ATCRBS or Mode-S transponders, for example) must pass a battery of tests every 24 months (Federal Aviation Regulations Part 43, Appendix F). The tests include, among other items, verification of transponder output power, transponder output frequency, and transponder receiver sensitivity. Currently, this testing is accomplished through ramp testing or bench testing, and expensive equipment may be required to complete this hours-long time-consuming process. Further, current testing is performed at required test intervals, and it may be difficult for aircraft operators to know whether installed transponders are operating correctly and within established tolerances until failure is detected when the periodic test is performed. What is needed, then, is a means to test transponder performance without the use of dedicated external test equipment. What is also needed is a means to monitor performance of a transponder at periodic intervals or on a continuous or semi-continuous basis. What is also needed is a method to monitor trends in transponder performance and identify when operating parameters are deviating from desired ranges.